Multiple compartment package



Dec 27, 1956 w. s. SCHNEIDER ETAL 3,294,227

MULTIPLE COMPARTMENT PACKAGE Original Filed Dec. l1, 1962 United States Patent 3,294,227 MULTIPLE COMPARTMENT PACKAGE William S. Schneider, Glendale, and Arthur P. Corella,

North Hollywood, Calif., assignors of ten percent toV This application is a continuation of oui co-opending application of the same title, iiled December 1l, 1962, Serial No. 243,948 which in turn is a continuation-inpart of our two earlier applications, Serial No. 769,608 iiled October 27, 1958 and Serial No. 100,165 led April 3, 1961, now abandoned for Multiple Compartment Package.

The present invention is concerned generally with containers and packages made from thin flexible materials which permit production of a package which is flexible and easily deformable; and the invention is more particularly concerned with packages of this type which are divided interiorly into two or more compartments separated from each other by rupturable barrier means which can be broken without rupturing the outer walls of the package to permit intermingling of the contents of two adjoining compartments.

Packages of this type typically have two compartments disposed one at either side of the rupturable barrier means,l although it will be understood that the present invention is not limited to this particular number of compartments. Such packages are designed to hold two or more different substances, one substance in each compartment, isolated from each other in such a way that they can be stored without any intermingling of the several contents until needed. The substances in the container may be in the form of a dry material in powder or tablet form, or a liquid, in either or both compartments. However, for purposes of disclosure and in order to bring out the particular advantages of the present invention, it is assumed that one compartment contains a liquid and the other a dry, powdered substance.

By breaking the barrier while maintaining the external walls of the package intact, the substances in the two compartments can be mixed together within the interior space of the container. A container of this character requires that the walls be flexible and strong, so that the package walls can be deformed as necessary to force the contents from one compartment to the lother and back again to the extent necessary to effect mixing of the ingredients. Containers for this type of Iuse also require barrier means able to elect complete separation of the two compartments until mixing is desired but which can then be brokenV at will in a manner to open up a passage at a predetermined location between the two compartments through which the substances can move between compartments. This barrier between the compartments isolates the contents of each compartment during the storage period and is strong enough to prevent .premature rupture; but at the same time, the barrier is ideally of such strength that it can be broken easily at the proper time.

Various designs for containers and packages of thisv general character have been evolved, but each known design has one or more disadvantages that have prevented if from becoming widely useful.

In some designs, there is provided an interior wall or membrane of substantial area, for example a wall which is connected to the package walls at one end of t-he pack- ICC age and extends for a large part of the length of the package. A wall of this character is subject to premature failure as a result of ilexing fatigue occurring at positions of maximum curvature. The area of the wall is so great that movement of the contents ofthe package, particularly liquid contents, causes repeated movement ofthe wall with bending or flexing at points of relatively sharp curvature. Eventually, this results in weakening of the wall and sometimes in the creation of cracks or pin -hole perforations which render the barrier ineffective. Another disadvantage of the large area of an interior wall of this type is that many materials used for this purpose are not impermeable to vapors and, consequently, the large wall area permits signicant transfer of a vapor through the wall when the package is stored for a period of time.

In other designs of packages, the barrier means extends from one cut edge of the package to the other cut edge. If the barrier is internally weak, as it normally is, there is a danger that rupture of the barrier by the creation of internal lstresses or pressures within the liquid contents of one compartment will rupture the barrier in such a manner as to permit the contents to leak out of the package through the barrier at one cut edge of the package. To avoid this type of failure it has been proposed to pull the walls apart centrally of the package by grasping the walls. This is difficult to do under the best of conditions, making the package cumbersome and inconvenient to use. Sometimes the problem has been solved by applying externally of the package suitable tabs or other means which may be grasped in order to pull the walls apart. While this makes the package more convenient to use, it makes' the package more expensive and creates additional problems of manufacture which are substantial.

It has also been proposed to provide a rupturable barrier by sealing the outer walls of the package together directly by a simple bar seal formed by the application of heat and pressure, the object being to provide a sealy which is suilciently weaker than the marginal seals that the central bar seal breaks rst and much more easily. This type of seal has been proved Iunsuitable where the seal between the compartments is to be broken in a controlled manner. The strength of the seal depends upon both the temperature reached by the outer walls and the pressure applied by the sealing heads; and even small variations in either factor often result in wide variations in the strength of the seal. If caution is exercised to prevent the seal from becoming too strong to be broken easily, then the seal produced is often too weak and breaks prematurely. From a practical standpoint, a seal of this type between the container walls is highly unsatisfactory because of the wide variation in breaking strength, and the inability to' provide by production machines a seal of closely predictable or uniform strength.

A variation of this latter type of seal is one in which the strength of the seal between the package walls is controlled by the application to the walls of a chemically active inhibitor. An example of this is the use of an inhibitor on package walls having an internal sealing layer of polyethylene. The strength of the seal produced then is dependent upon and varies with the amount of inhibitor applied to the package walls byan applicator. Experience indicates that it is not possible. to control closely thev amount of the inhibitor applied so as to obtain a uniform breaking strength; The polyethylene and the inhibitor normally differ somewhat in their chemical properties from batch to batch and as a consequence the chemical reaction between them is not always uniform, a factor which adds to the variation in strength of the seals. It has also been found that seals of this type are affected adversely by age and relatively low temperatures, both these conditions reducing the seal strength and increasing the likelihood of premature rupture of the barrier.

A limitation upon the use of an inhibitor is that there is no universal inhibitor which is satisfactory with all types of web stock used in making packages, and consequently, some types of webs for packages cannot be treated in this manner to make a rupturable barrier.

Another known construction is to provide a barrier comprising a strip sealed to the package walls and having a cut edge exposed interiorly of the package. The strip is impregnated at the cut edge with a liquid to render the strip impervious to liquids. The breaking strength of the strip then varies with the depth and degree of penetration of the impregnating liquid. Since these are factors that cannot be closely controlled, the breaking strength varies Widely and beyond acceptable limits.

In general, prior designs may be characterized as not lending themselves to adequate control of the strength of the seal so that a uniform breaking strength is obtained. This is necessary in order to avoid accidental or premature rupture of a Weak or sub-standard seal in shipment or as a result of repeated handling of the package, or t avoid production of a seal having highly inconvenient excessive strength.

Thus, it is a general object of the present invention to provide in a package of the character described a barrier rupturable by internal pressure and so designed as to be capable of a closely controlled or predictable breaking strength.

A further object is to provide a rupturable barrier in a package of this character which is free from the danger of failure as a result of repeated flexing or fatigue.

Another object is to provide a package of the character described having a rupturable barrier which is suited to a wide range of materials without any change in the basic design, thus permitting the use of materials which will permit obtaining special characteristics such as impermeability to vapors, inertness with respect to water or other liquids or chemicals which may be packed in the package, and can be used with a wide variety of webs forming the outer walls. p

A further object is to provide a barrier in a package of this type in which there is no cut edge of the barrier exposed to liquid contents in at least one compartment in order to avoid any absorption of liquid or weakening of the barrier by action thereon of the liquid within the compartment.

In order to be economically handled, it is an object of the invention to provide a barrier for a package of this type which is adapted to known designs of automatic packaging machines of the form and fill type. This eliminates the need of building special machines to handle a particular type of barrier and also makes it possible to produce in one operation a complete filled package instead of making containers which are subsequently filled and then finally sealed.

These and other objects of the invention have been attained in a compartmented package having two adjacent compartments adapted to hold and mix a plurality of components of which one is typically a liquid, said package comprising a flexible bag formed by two opposed, similarly shaped outer walls secured to each other to define between them the interior space within the bag, and rupturable barrier means between and secured to the two outer walls of the bag and comprising a thin film of a heat-sealing thermoplastic compound sealed to the outer walls at substantially opposed locations on the inner faces of said walls and a backing strip secured to the film and coextensive therewith. The backing strip and film are in the shape of a narrow, elongated sheet or strip folded longitudinally into a U-shape and the outer faces of the arms of the folded U-shape are sealed to the walls of the package with the intervening portion of the U-shape extending between the two outer walls whereby the film is placed in tension by outwardly directed forces exerted on the two outer walls by the contents of one compartment.

The result is that the barrier breaks by breaking the film in tension at the fold of the U-shape barrier and the remainder of the barrier ruptures along a line of weakness within the material of the backing strip or at the interface between the backing strip and the film because of the character of the bond of these two elements.

In one embodiment of the invention, the barrier strip is metal foil to which the film bonds with a sufficiently low strength of adhesion that rupture of the barrier is accomplished by breaking the bond between the backing strip and the film. If the metal foil is reduced in thickness suiiiciently, rupture of the barrier may involve a tension break in the metal foil. Generally speaking, the backing strip on the barrier means is a material offering relatively low resistance to rupture of the barrier compared with the tensile strength of the film itself.

Reference herein to sealing by the appliction of heat and pressure includes so-called electronic sealing or induction heating methods wherein heating is accomplished by energy in the form of short wave radiant energy.

How the above objects and advantages of the invention, as well as others not specifically referred to herein, are attained will be more readily understood by reference to the following description and to the annexed drawing, in which:

FIG. 1 is a perspective view of a typical but preferred multiple compartment package having two compartments and constructed from flexible sheet material according to the invention.

FIG. 2 is an enlarged section on line 2-2 of FIG. 1.

FIG. 3 is an enlarged fragmentary section on line 3-3 of FIG. l.

FIG. 4 is an enlarged fragmentary section on line 4-4 of FIG. l showing the end of the barrier embedded in a marginal seal of the package.

FIG. 5 is a view similar to FIG. 2 illustrating one type of rupture of the barrier.

FIG. 6 is a View similar to FIG. 2 showing rupture of the barrier wherein the backing strip and the sealing film separate.

FIG. 7 is a View similar to FIG. 2 of a variational embodiment in which the arms of the U-shaped barrier are not sealed together.

FIG. 8 is a view similar to FIG. 7 illustrating a stage in the rupture of the barrier.

FIG. 9 is a fragmentary section similar to FIG. 2 showing a variational embodiment.

Referring now to the drawing, and more particularly to FIG. l, there is shown therein a preferred but typical package, indicated generally at l0, embodying the present invention. outline since this shape is most commonly and easily produced on packaging machines, but it will be understood that the invention is not necessarily limited to any particular shape of package or container.

The package comprises two opposed, similarly shaped outer walls 11 and 12, seen especially in FIG. 2, which overlie one another and which are secured together t0 form between them a sealed flexible bag having an interior space within the bag. These outer walls are generally joined together around the pehirphery of the package, the purpose being to provide a seal around the interior space; and the invention is independent of the particular means employed to join together the two walls. For example, the package may be formed from a length of seamless tubing. In this case the walls 11 and 12 are integral with each other along two opposite edges of the completed package while the two walls are s ealed together, in any suitable manner, along each of the remaining two opposite ends.

This package is shown as being of rectangular However, it is a more common practice to make a package of this type either from a single sheet or web which is folded over on itself along a median line to provide the two overlying walls which are integral at one edge of the package, or from two separate sheets or webs of the same size. When made from a single sheet, the marginal sealed area connecting the two sheets extends around three sides of the completed package. When made from two sheets, the final container appears as shown in FIG. l and it is the same Width as each of the two sheets which are joined together by marginal sealed areas 14 extending around all four sides of the package. In any of these constructions walls 11 and 12 are each made from a thin sheet of flexible material of such a nature that the inside faces of the container can be sealed to each other by the application of heat and pressure in ways that are Well known in the art. In a typical case, the walls 11 and 12 are flexible sheet material, such as cellulose acetate film commonly known as Cellophane, coated with a layer or film of polyethylene about 2-3 mils thick on the inside surfaces that oppose each other. The polyethylene is a thermoplastic material which permits the walls to be sealed to each other by the application of heat and pressure. Subject to considerations mentioned below, the thickness of the polyethylene layer may be increased or decreased. For the sealing layer other thermoplastic materials such as vinyl or rubber hydrochloride may be used instead of polyethylene.

The space inside the package between walls 11 and 12 is sub-divided into two separate compartments 16 and 17 by barrier means 20 interposed between the two walls and joined to both of them. The barrier means 20 extends transversely of the package between two marginal sealed areas 14 and has its ends embedded in the respective sealed areas for reasons which will be explained more fully. Barrier means 20 preferably does not extend to the edges of the package; its length is less than the package width and so terminates somewhat short of each of the two opposite edges a as may be seen in FIGS. l and 4.

Generally speaking, barrier means 20 is a composite member comprising an outer layer or film of a heat-sealing thermoplastic compound having a relatively high tensile strength and which is sealed to the outer walls 11 and 12, and an inner layer or backing strip secured to the outer layer or film and offering less resistance to rupture of the barrier than the outer layer or film, as will be further explained. Of course, the barrier as a whole has less resistance to rupture than the container walls or the marginal sealed areas 14 since it is desired that the barrier between the compartments 16 and 17 break prior to creation of any break or opening in the walls through which contents of the package can escape.

In the specific embodiment of the invention illustrated in FIG. 2, the center layer of barrier 20 consists of a narrow elongated sheet or strip 22 of a relatively low tensile strength material. One example of a suitable material is a fibrous or paper-like material. Layer 22 is coated on each side with a layer 21 and 23 of a suitable thermoplastic material having heat-sealing characteristics. A common and widely used material of this character is polyethylene, although other similar compounds are well known. For this purpose, it has been found very satisfactory to employ a layer of polyethylene which is about one mil (l/ 1000 inch) in thickness, it generally being unnecessary to make the polyethylene more than one and one-half mils in thickness. j

Elongated sheet 22, coated on both sides with layers 21 and 23, is initially flat. To form the barrier itis first folded longitudinally over and upon itself into a U-shape as shown particularly in FIG. 2. In the drawing the thickness of all elements of the barrier is exaggerated for purposes of illustration. The folded barrier is then inserted between two sheets forming walls 11 and 12 of the completed package, and heat and pressure are then applied externally of walls 11 and 12 at opposite sides of the barrier. The result is that the mutually engaging inner surfaces of the U-shape barrier formed by the layer 21 are sealed together since the inside layer of polyethylene is heat scalable to itself. At the same time the outside surfaces of the strip are sealed by the outer layer 23 to the inside surfaces of container walls 11 and 12. It will be noted in FIG. 2 that the outer faces of arms of the folded U-shape are sealed to the outer container walls at substantially opposed locations ony the faces of the walls.

In the exemplary structure illustrated in FIGS. 1 and 2, it is assumed that the package is made of two separate webs, each having on its inner, mutually opposing face a layer 11a and 12a respectively of a thermoplastic sealing compound, for example polyethylene. The outer walls 11 and 12 are joined together over marginal areas 14 by the application thereto of heat and pressure, the heat sealed areas 14 extending continuously around the four sides of the package seen in FIG. l. The ends of the barrier are spaced inwardly from package edges 10a and are embedded in the heat sealed areas at opposite sides of the package. To facilitate this, the heat sealed areas may be widened or extended inwardly of the package at the barrier means, as indicated at 14a, in order to provide an enlarged sealed area around each end of the barrier 20. While barrier 20 is here illustrated as located approximately midway between opposite ends of the package to provide compartments 16 and 57 of substantially equal size, it will be understood that the position of the barrier may be changed as desired to produce compartments of I different sizes or even different shapes.

Barrier 20 isolates one compartment from the other. The loop in the folded barrier sheet is exposed to the contents of compartment 17, which is the compartment containing liquid. Thus, the polyethylene coating, which is substantially impervious to the liquid, protects layer 22 from contact with an absorption of the liquid.

Although the advantages of the present invention are especially apparent when compartment 17 is filled with a liquid, it will be understood that a container of this same construction may contain a dry or powdered substance in both compartments.

When it is desired to mix together the contents of the two compartments, pressure is applied manually to the exterior surface of the compartment containing the liquid. This externally applied pressure causes a corresponding internal pressure which, because of the liquid nature of the contents of compartment 17, is exerted outwardly in all directions equally upon walls 11 and 12 and barrier 20. The result is that walls 11 and 12 are spread apart in the immediate vicinity of the loop in barrier 20 and this portion of the barrier means is placed in tension. Stresses in the barrier loop are concentrated in the outer layer of polyethylene film 23 in tension at 23a. By applying suflicient external pressure, the tension forces in the layer at 23a reach a predetermined value sufficient to break the layer. This is the first stage. Once the film breaks at 23a, the remainder of the barrier ruptures during the second stage of the break along a line of weakness extending between the two portions of the sealing layer 23 sealed to the two outer walls 11 and 12. In the barrier construction illustrated in FIG. 2, this line passes through one arm of the barrier and more precisely through one arm of the layer 22. This layer is accordingly selected from a material which is easily broken or pulled apart in tension so that the rupture of the barrier follows a line of weakness established by the low tensile strength layer 22. Hence, the rupture occurs along the line 25. One example of a suitable material for layer 22 is a fibrous material, especially one weakened by contact with water or other liquids, such as a low-wet strength paper.

Rupture occurs essentially in two stages. is rupture of the outer sealing layer in tension, followed by the remainder of the barrier. The barrier is so con- The first structed that the resistance to rupture of the barrier during the second stage is much less than during the rst stage. Accordingly, rupture strength is controlled effectively by the breaking strength in tension of the outer sealing layer 23. Backing strip 22 serves several purposes, an important one of which is to permit proper handling and tracking of the sealing layer 23 when the packages are made on automatic form and fill type machines.

Polyethylene or other material from which sealing layers 21 and 23 are made has a comparatively uniform tensile strength which is well known and can be very closely controlled in the manufacture of the material. Accordingly, the strength in tension of layer 23 is substantially proportional to the thickness of the layer and this in turn can be closely controlled during the applica- -tion of the sealing layer to backing strip 22. In actual practice it has been found that the strength of sealing layer 23 can be held to a predetermined value within a tolerance of plus or minus 21/2 percent. The purpose of making this layer only approximately one mil in thickness, more or less, is to insure that this film is adequately strong to withstand the incidental stresses applied to it but still weak enough to break before the container breaks at any other point as the result of the pressure purposely applied to the liquid within compartment 17. Since the inside surface of each wall 11 and 12 is coated with a layer 11a or 12a respectively of polyethylene, usually about 2-3 mils thick, the bond between these walls in the sealed areas 14 consists of polyethylene totaling 4-6 mils in thickness. Likewise, the bond between one of these walls and sealing layer 23 has a thickness of about 3 mils or perhaps more. Thus, the layer at wall 23a is thinner and less resistant to rupture by pressure within compartment 17 than the container walls or the joints therewith at any other point.

Since the seal between the two outer walls 11 and 12 and the areas 14a is stronger than sealing layer 23, areas 14a prevent rupture of the barrier at these locations and confine the rupture of the barrier to the central area thereof. In practice, it is true that the tension forces exerted on the outer sealing layer of the barrier are greatest at the center of the barrier so that most of the breakthroughs occur centrally of the barrier.

When backing strip 22 is a relatively weak, fibrous material it generally is further weakened by the exposure to the liquid that occurs after the barrier is broken as described. For some uses of the two-compartment package, it is contemplated that the package contents will be retained within the package for some time after rupture of the barrier. Under these conditions, the liquid can seep or leak through such a backing strip by capillary action longitudinally of the barrier. By stopping the barrier short of the edges a of the package, as shown in FIG. 4, the extreme ends of the barrier are surrounded and sealed by marginal areas 14 to prevent loss of liquid to the exterior of the package through backing strip 22.

To facilitate opening the container and discharging the mixed contents, it is preferred to provide the container at one corner with a pouring channel 28 which extends into but is closed at its outer end by a portion of the sealed marginal areas 14. The container is formed with a line of weakness, typically a row of perforations 29, which intersects pouring channel 28 near its outer end. This line of weakness not only indicates t-he proper location of a tear in the material, but guide the tearing when manually performed, so that the pouring channel is opened across its outer end by removing the corner of package 10. The desired result is a discharge opening of a limited size through which the contents of the container may be discharged by squeezing the container.

A modified form of the invention is shown in FIG. 6 in which barrier means a has been constructed by substituting metal foil 32 for fibrous layer 22 of the barrier previously described. This layer of metal foil is typically of the order of one mil, more or less, in thickness and typically is aluminum foil which serves as a backing strip for the outside layer of heat sealing material 23.

A package containing a barrier of this construction has the same general characteristics as already described. The barrier has an inherent line of relative weakness, i.e., low resistance to rupture along the interface between the outer layer 23 of sealing material and the foil layer 32. Consequently, the barrier, after the first stage of rupture, breaking the outer film 23 in tension, ruptures along the line 25a indicated in FIG. 6. In this case the outer layer 23 of thermoplastic sealing material has a lower resistance to separating from the foil than the foil layer has to internal rupture. Consequently, the forces tending to separate outer walls 11 and 12 pull the thermoplastic layer from the metal foil so that the second stage of rupture occurs along the line 25a of relative weakness between the two portions of the sealing layer secured to the outer walls.

A particular advantage of the metal foil is its imperviousness to certain liquid chemicals as well as to the transmission of mositure and other gases. Although polyethylene and other suitable thermoplastic compounds which may be used on the exterior of the barrier are commonly referred to as liquid imprevious, they do have a very small but definite permeability to vapors over a long period of time. This permeability can be substantially reduced or eliminated by incorporating a layer of metal foil in the barrier as shown.

There is shown in FIG. 7 a further modified form of the invention in which the barrier 20b is of the type which may be generally described as an open U-shape since the two arms of the folded strip are not sealed together. In the embodiment of FIG. 7, the barrier may be considered as being constructed in the same manner as the barrier in FIG. 2 except that the inside layer 21 of heat sealing material is omitted. Consequently, the barrier has only one heat sealable surface; and when the strip is folded longitudinally into the U-shape illustrated the heat sealable surface is facing out and is sealed to the walls 11 and 12 of the package. The mutually engaging inner surfaces of the folded barrier are the surfaces of backing strip 22 which do not adhere to each other.

This barrier ruptures in a two-stage break generally similar to the .process previously described. The first stage is a tension break of the outside sealing layer 23 which is placed in tension at loop 23a by forces tending to separate package walls 11 and 12. Upon breaking in tension, the relatively high tensile strength sealing layer is no longer available to resist forces separating the package walls and the entire stress is then applied to layer 22 which is a material having a much lower tensile strength than the heat sealing layer. As a result, the second stage of the break is a rupture in tension of layer 22 with the result that the barrier breaks along a line 25b. As before, it will be seen that here the barrier ruptures along a line of relative weakness which extends between the two portions of the sealing layers attached to the outer Walls 11 and 12.

Another example of barrier means of the open U-shape is shown in FIG. 8 in which the barrier means 20c is constructed in the same manner as barrier 20a of FIG. 6 except that the inner sealing layer 21 is omitted. As a consequence, the barrier 20c consists of the two layers, metal foil 32 and the outer layer of heat sealing material 23 by which the barrier is sealed to package walls 11 and 12. The inner faces of the U-shape are not sealed together.

This type iof barrier may break along either of two lines depending upon where the line of relative weakness is placed by its construction. As in all other forms of barrier, the first stage of rupture is a tension break of the outer heat sealing layer at the loop 23a. Thereafter the rupture progresses either along the interface between the heat sealing layer and the metal foil, as in FIG. 6, or

through the metal foil along the line 25b located as in FIG. 7. The deciding factor is the relative strength of the bond between the metal foil and the heat sealing layer compared with the strength of the metal foil in tension. If the foil is very thin, perhaps only one-third t-o one-half of a mil in thickness, its tensile strength is so low that it ruptures in tension at the fold and the break thus resembles the break along the line 25h of FIG. 7. On the other hand, if the layer of foil is made thicker for example in excess of one mil, then it may be sufciently strong in tension to resist breaking at this point and as the result the bond between the foil and the heat sealing layer, being relatively weaker, becomes the location of the second stage of the rupture.

In the so-called open U-shaped of barrier (FIGS. 7 and 8) in the inner opposed faces o-f the 'barrier are not sealed together. Consequently, the package contents, whether liquid or solid, can ow longitudinally of the barrier and escape outside the package unless a positive seal is provided. This is accomplished by terminating the barrier short of the package edge and embedding the ends in sealed areas 14a so that the seal between outer walls 11 and 12 closes the ends of the barrier to prevent leakage out of the package.

Generally speaking, it is preferable to seal as much as as possible of the barrier means to side walls 11 and 12, leaving free between the walls only the curved portion of the folded barrier at the base of the U-shaped, as for example in FIGS. 2 0r 7. At the same time, it is necessary to avoid oversealing which would seal together the outer walls 11 and 12 beyond the fold. In practice, it is necessary to allow for errors in tracking of the barrier stock, movement of the web, position of the sealing heads and so forth; and for this reason the area on the barrier sealed to the walls may be moved slightly back from the fold.

This results in the variation of FIG. 9 when the barrier means of the open U-shape, as in FIG. 8, is sealed to package walls 11 and 12 over a width less than the full length of the arms of the folded U-shape. When walls 11 and 12 are then separated at the middle of the package by the contents, the barrier is then stretched into a wide U-shape. This construction advantageously enlarges the volumetric capacity of the compartments for the same area of sheet materials in the walls II and 12. Another advantage of this narrower seal is that the pac] age is more ilexible and can be bent or folded more readily along the barrier itself. Rupture occurs in the same way previously described, normally starting at or near to the curved portion of the barrier adjoining an outer wall where a concentration of stresses occurs.

The package described has a continuous perimetral seal since this package is formed, filled and sealed in a single operation. However, the improved barrier means is equally applicable to a partially completed package in which the compartment 17 remains empty until some subsequent time when the water is added by the ultimate user. Such a package is described in our co-pending application Serial No. 100,165 referred to above and is made by placing pouring channel 28 to communicate with the liquid holding compartment and making the marginal seal 14 discontinuous at the pouring channel to permit said compartment to be filled. The channel can be held closed by any suitable means, for example the thumb and forenger, to seal compartment 17 during the rupture of the barrier and the subsequent mixing period.

Among the possible modification of the package described is the substitution of a powder for the liquid in compartment 17. Under this circumstance, it may be desired to deliberately introduce a quantity of air into the compartment to assist in rupturing the barrier means in the manner already described. Air being a fluid acts in the same manner as liquid to break the barrier when external pressure is applied, even though the air is cornpressible.

The several objects of the invention are achieved most fully in the closed U embodiment illustrated in FIGS. 2-6. The barrier offers maximum resistance to transfer of any liquid or gas between compartments, but at the same time its breaking strength is closely controlled and easily reproducible as it is determined by the strength of the thin lm at the fold in the barrier. Sealing the arms of the U-shape together prevents ilexing of the barrier and eliminates premature failures from flexing fatigue. In the open U-shape of FIGS. 7 and 8, the backing strip can be selected to give a high degree of impermeability to liquids and gases and also to reinforce the barrier against flexing fatigue.

Both forms of the folded barrier achieve other objects of eliminating cut edges in contact with liquid contents, sealing ends of the barrier to prevent leakage at the ends, maximum versatility and flexibility in use of materials, and accurately predictable breaking strength.

From the foregoing description it will be appreciate that Various changes may be made in the construction of the present invention without departing from the spirit and scope thereof. Accordingly, it is to be understood that the above description is to be considered as being illustrative of, rather than limitative upon, the invention as defined by the appended claims.

We claim:

1. A compartmented package adapted to hold'and mix a plurality of components and having at least two adjacent compartments of which one is adapted to hold a liquid, comprising: a flexible bag having two opposed, similarly shaped outer walls secured to each other to form between them an interior space within the bag; and rupturable barrier means between and secured to the two outer walls to divide the interior space into two separate compartments, said barrier means comprising an elongated sheet having a rst layer of heat sealing thermoplastic compound and a backing layer bonded to the first layer, and folded longitudinally into a U-shape with the heat sealing layer outside and the respective arms of the U-shaped heat sealed by the first layer of heat sealing thermoplastic compound to opposed areas on the inside faces of the outer walls of the bag placing the loop portion of the heat sealing layer between the outer walls and exposed to liquid in said one compartment; said barrier means being constructed to be ruptured by forces that tend to spread the outer walls apart and place the rst layer under a predetermined tension at the loop therein, the barrier means rupturing along a line of relative weakness between the two portions of the first layer sealed to the outer walls whereby liquid can flow from said one compartment to the other along a path following said line of rupture, said backing layer of the barrier means consisting of a sheet co-extensive with said layer of heat sealing thermoplastic compound and the heat sealable bond between the heat sealable thermoplastic compound and said backing layer being of less strength than the corresponding bond between the heat sealable compound and the walls of said bag to provide the line of rupture when the walls of the bag are spread apart to subject the barrier to rupture forces.

2. A compartmented package adapted to hold and mix a plurality of components and having at least two adjacent compartments of which one is adapted to hold a liquid, comprising: a exible bag having two opposed, similarly shaped outer walls secured to each other to form between them an interior space within the bag; and rupturable barrier means between and secured to the two outer walls to divide the interior space into two separate compartments, said barrier means comprising an elongated sheet having a rst layer of heat sealing thermoplastic compound and a backing layer bonded to the rst layer, and folded longitudinally into a U-shape with the heat sealing layer outside and the respective arms of the U-shape sealed to opposed areas on the inside faces of the outer Walls of the bag placing the loop portion of the heat sealing layer between the outer walls and exposed to liquid in said one compartment; said barrier means being constructed to be ruptured by forces that tend to spread the outer walls apart and place the first layer under a predetermined tension at the loop therein, the barrier means rupturing along a line of relative weakness between the two portions of the first layer sealed to the outer walls whereby liquid can flow from said one compartment to the other along` a path following said line of rupture, said backing layer of said barrier means comprising a sheet having a layer of heat sealing thermoplastic compound on both sides thereof, the folded barrier means having the inner opposed surfaces of the U-shaped sealed to other other, and wherein the backing layer of the barrier means is metal foil and the line of rupture of the barrier is established along said line of relative weakness located at the interface between .the metal foil layer and the layer of heat sealing compound.

3. A compartmented package adapted to hold and mix a plurality of components and having at least two adjacent compartments of which one is adapted to hold a liquid, comprising: a flexible bag having two opposed, similarly shaped outer walls secured to each other to form between them an interior Space within the bag; and rupturable barrier means between and secured to the two outer walls to divide the interior space into two separate compartments, said barrier means comprising an elongated sheet having a first layer of heat sealing thermoplastic compound and a backing layer bonded to the first layer, and folded longitudinally into a U-shape with the heat sealing layer outside and the respective arms of the U-shape sealed to opposed areas on the inside faces of the outer walls of the bag placing the loop portion of the heat sealing layer between the outer walls and exposed to liquid in said one compartment; said barrier means being constructed to be ruptured by forces that tend to spread the outer walls apart and place the first layer under a predetermined tension at the loop therein, the barrier means rupturing along a line of relative weakness between the two portions of the first layer sealed to the outer walls whereby liquid can flow from said one compartment to the other along a path following said line of rupture, said barrier means comprising a sheet having a layer of heat sealing thermoplastic compound on one side only of the backing layer and the surfaces of the sheet inside the folded U-shaped are not sealed to each other, and wherein the barrier means comprises a backing layer of metal foil, and the line of rupture of the barrier means is established along said line of relative weakness located at the interface between the metal foil layer and the layer of sealing compound sealed to an outer wall.

4. A flexible, multiple compartment container cornprising:

two mutually overlying flexible walls joined together to define between them the interior space of the container; and rupturable barrier means between and joined to the walls to divide the interior space into two separate compartments within the container of which one compartment contains a liquid, said barrier comprising a strip of a low tensile strength material and a layer on both sides of said strip of a heat sealing compound, at least one of said layers being also a liquid impervious compound, said strip being folded on itself with the mutually engaging surfaces of the sealing layer inside the folded strip sealed to each other and with the liquid impervious layer exposed on the outside of the folded strip and sealed to the container walls except for an intervening area at the fold in the strip which is exposed to liquid in said one compartment; said strip being weaker than the layers of sealing compound sealed to said Walls and said barrier being rupturable beginning at the fold by forces spreading the adjoining container walls apart and breaking the outer sealing layer at the fold and progressively rupturing the barrier along a line passing between the two outer sealing layers of compound sealed to the container wall and through the strip of low tensile strength material whereby the liquid can flow into the other compartment along a path following said line.

5. A container as Vclaimed in claim 4 in which the strip material of the barrier is a fibrous material weakened by absorption of said liquid when the outer layer of sealing compound is broken.

6. A container as claimed in claim 5 in which the strip of material is made of low wet strength paper.

7. A flexible, multiple compartment container comprising: two mutually opposed, flexible walls sealed together face-to-ace over marginal areas at two opposite margins of the container and rupturable barrier means between and sealed to the two walls to divide the interior space of the container into two separate compartments within the container of which one compartment is filledwith liquid, the barrier means extending across the interior of the container and having the ends of the barrier means sealed in said marginal sealed areas at opposite margins of the container, said barrier means comprising a strip of paper-like material of low tensile strength that is weakened by contact with said liquid covered on both sides with a layer of liquid impervious sealing compound t0 preclude exposure of the strip to said liquid and then folded longitudinally over on itself, the outer surfaces of the folded barrier means being sealed to the two container walls whereby the outer layer of sealing compound at said fold is placed in tension when the two container walls are urged apart at the barrier means by externally applied pressure on the liquid in said one compartment to rupture the outer layer at said fold to expose the strip to said liquid and thereby weaken the strip.

8. A compartmented package adapted to hold and mix a plurality of components and having at least two adjacent compartments of which one is adapted to hold a liquid, comprising:

a flexible bag having two opposed, similarly shaped outer walls secured to each other to form between them an interior space within the bag;

rupturable barrier means between and secured to the two outer walls to divide the interior space into two separate compartments, said barrier means comprising an elongated sheet having a first layer of heat sealing thermoplastic compound and a backing layer bonded to the first layer, and folded longitudinally into a U-shape with the heat sealing layer outside and the respective arms of the U-shape heat sealed by the first layer of heat sealing thermoplastic compound to opposed areas on the inside faces of the outer walls of the bag placing the loop portion of the heat sealing layer between the outer walls and exposed to liquid in said one compartment; said barrier means having a rupture zone in which the backing layer on the inside of the U-shape has opposing surfaces not heat scalable to each other and in which zone the barrier means is rupturable by forces that spread the outer walls apart and place the barrier under tension at the loop therein, the strength 0f the composite sheet in tension on the cross-section at the loop being less than the strength of the bond with the outer walls and rupture taking place along a path of relative weakness passing between the two portions of the rst layer sealed to the outer walls whereby liquid can flow from one compartment to the other along said path;

and sealing means closing the ends of the folded sheet beyond the rupture zone to prevent escape of the contents from the interior of the package between the arms of the folded U-shape.

9. A compartmented package according to claim 8 in which the sealing means closing the ends of the folded s heet is provided by heat sealed areas at opposite margins 13 14 of the package, the strip being embedded at its ends in References Cited by the Examiner said areas With ends of the strip spaced from the edge UNITED STATES PATENTS of the Package' 2,885,104 5/1959 Greenspan 20e-47 X 10. A compartmented package according to claim 8 in which the backing layer of the strip is weaker in tension 5 2932385 4/1960 Boumeler et al 206-47 at the loop than the layer of heat sealing compound. LOUIS G M ANCENE Primary Emmi-en 

1. A COMPARTMENTED PACKAGE ADAPTED TO HOLD AND MIX A PLURALITY OF COMPONENTS AND HAVING AT LEAST TWO ADJACENT COMPARTMENTS OF WHICH ONE IS ADAPTED TO HOLD A LIQUID, COMPRISING; A FLEXIBLE BAG HAVING TWO OPPOSED, SIMILARLY SHAPED OUTER WALLS SECURED TO EACH OTHER TO FORM BETWEEN THEM AN INTERIOR SPACE WITHIN THE BAG; AND RUPTURABLE BARRIER MEANS BETWEEN AND SECURED TO THE TWO OUTER WALLS TO DIVIDE THE INTERIOR SPACE INTO TWO SEPARATE COMPARTMENTS, SAID BARRIER MEANS COMPRISING AN ELONGATED SHEET HAVING A FIRST LAYER OF HEAT SEALING THERMOPLASTIC COMPOUND AND A BACKING LAYER BONDED TO THE FIRST LAYER, AND FOLDED LONGITUDINALLY INTO A U-SHAPE WITH THE HEAT SEALING LAYER OUTSIDE AND THE RESPECTIVE ARMS OF THE U-SHAPED HEAT SEALED BY THE FIRST LAYER OF HEAT SEALING THERMOPLASTIC COMPOUND TO OPPOSED AREAS ON THE INSIDE FACES OF THE OUTER WALLS OF THE BAG PLACING THE LOOP PORTION OF THE HEAT SEALING LAYER BETWEEN THE OUTER WALLS AND EXPOSED TO LIQUID IN SAID ONE COMPARTMENT SAID BARRIER MEANS BEING CONSTRUTED TO BE RUPTURED BY FORCES THAT TEND TO SPREAD THE OUTER WALL APART AND PLACE THE FIRST LAYER UNDER A PREDETERMINED TENSION AT THE LOOP THEREIN, THE BARRIER MEANS RUPTURING ALONG A LINE OF RELATIVE WEEKNESS BETWEEN THE TWO PORTIONS OF THE FIRST LAYER SEALED TO THE OUTER WALLS WHEREBY LIQUID CAN FLOW FROM SAID ONE COMPARTMENT TO THE OTHER ALONG A PATH FOLLOWING SAID LINE OF RUPTURE, SAID BACKING LAYER OF THE BARRIER MEANS CONSISTING OF A SHEET CO-EXTENSIVE WITH SAID LAYER OF HEAT SEALING THERMOPLASTIC COMPOUND AND THAE HEAT SEALABLE BOND BETWEEN THE HEAT SEALABLE THERMOPLASTIC COMPOUND AND SAID BACKING LAYER BEING OF LESS STRENGTH THAN THE CORRESPONDING BOND BETWEEN THE HEAT SEALABLE COMPOUND AND THE WALLS OF SAID BAG TO PROVIDE THE LINE OF RUPTURE WHEN THE WALLS OF BAG ARE SPREAD APART TO SUBJECT THE BARRIER TO RUPTURE FORCES. 